BlackBerry Messenger is down again, despite RIM's assurances that everything would be fine. It seems lots of people can't get connected and partners are receiving notifications about ongoing problems.

Despite the fact that the Canadian company has replaced the failing core switch, the service fell down yet again, leaving many RIM customers to face another day without messaging or email.

Like a drunk in denial, RIM keeps telling us it is absolutely fine, before staggering around for a bit and finally collapsing in an unresponsive heap, leaving users disconnected and making the iPhone appear an increasingly attractive alternative.

A communication sent by RIM to business customers, and seen by El Reg, estimates the problems are affecting a quarter of BlackBerry users, who are now entering their third day of intermittent (at best) data services.

Those without their own BlackBerry Enterprise Server (BES) seem to be most affected, so the problem is hitting the consumer demographic RIM has been trying to attract, rather than its core business users – although some system administrators tell us they're still seeing problems despite running their own BES.

Email management company Mimecast, which provides continuity connections, tells us that only a small proportion of its BES-using customers have had problems, but even a small proportion is something business will be very concerned about.

The outage is certainly making a lot of people consider their commitment to RIM, and the timing is poor, as Apple's competitor to BBM, iMessage, is being launched later today.

Twitter is awash with complaints, celebrities chiming in with their opinions and suggestions that RIM try turning the server on and off again – not to mention jokes about three days of mourning for Steve Jobs and puns based around BlackBerry Crumble. ®